Vector Tracking Algorithm Based on Adaptive Cubature Kalman Filter

In the vector tracking loop, there is a great error in the output of discriminator owing to the disturbance of noise. Cubature Kalman filter is proposed to replace the discriminator to process I/Q data and generate code phase error and the carrier frequency error in this paper. The present algorithm not only can avoid the nonlinear problem of discriminator, but also can reduce the bad effect of noise. Moreover, using cubature Kalman filter to deal with the nonlinear I/Q data is beneficial to preserve the accuracy of data processing. Because noise is unknown or time-varying, the filter should have the ability to respond to the changes of environmental noise. The innovation of measurements is used to estimate the covariance matrix of measurement noise in real time. Finally, a comparison is carried out between the present algorithm and the vector tracking algorithm based on discriminator. The test results show that the code phase error and the carrier frequency error are smaller, and the accuracy of navigation solution is also higher.

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Performance and Evaluation of GNSS Receiver Vector Tracking Loop Based on Adaptive Cascade Filter

Remote Sensing ◽

10.3390/rs13081477 ◽

2021 ◽

Vol 13 (8) ◽

pp. 1477

Author(s):

Haotian Yang ◽

Bin Zhou ◽

Lixin Wang ◽

Qi Wei ◽

Feng Ji ◽

...

Keyword(s):

Covariance Matrix ◽

Traditional Method ◽

Phase Error ◽

Frequency Error ◽

Tracking Loop ◽

Loop Filter ◽

Noise Covariance Matrix ◽

Vector Tracking ◽

Noise Covariance ◽

Local Code

In the scenario of high dynamics and low C/N0, the discriminator output of a GNSS tracking loop is noisy and nonlinear. The traditional method uses a fixed-gain loop filter for error estimation, which is prone to lose lock and causes inaccurate navigation and positioning. This paper proposes a cascaded adaptive vector tracking method based on the KF+EKF architecture through the GNSS Software defined receiver in the signal tracking module and the navigation solution module. The linear relationships between the pseudo-range error and the code phase error, the pseudo-range rate error and the carrier frequency error are obtained as the measurement, and the navigation filter estimation is performed. The signal C/N0 ratio and innovation sequence are used to adjust the measurement noise covariance matrix and the process noise covariance matrix, respectively. Then, the estimated error value is used to correct the navigation parameters and fed back to the local code/carrier NCO. The field vehicle test results show that, in the case of sufficient satellite signals, the positioning error of the proposed method has a slight advantage compared with the traditional method. When there is signal occlusion or interference, the traditional method cannot achieve accurate positioning. However, the proposed method can maintain the same accuracy for the positioning results.

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Square-root cubature Kalman filter-based vector tracking algorithm in GPS signal harsh environments

IET Radar Sonar & Navigation ◽

10.1049/iet-rsn.2020.0317 ◽

2020 ◽

Vol 14 (12) ◽

pp. 1968-1975

Author(s):

Huibin Wang ◽

Yongmei Cheng ◽

Youmin Zhang

Keyword(s):

Kalman Filter ◽

Tracking Algorithm ◽

Harsh Environments ◽

Square Root ◽

Cubature Kalman Filter ◽

Vector Tracking

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Implementation and Performance Assessment of a Vector Tracking Method Based on a Software GPS Receiver

Journal of Navigation ◽

10.1017/s0373463311000440 ◽

2011 ◽

Vol 64 (S1) ◽

pp. S151-S161 ◽

Cited By ~ 7

Author(s):

Sihao Zhao ◽

Mingquan Lu ◽

Zhenming Feng

Keyword(s):

Global Positioning System ◽

Carrier Frequency ◽

Gps Receiver ◽

Tracking Loop ◽

Frequency Tracking ◽

Tracking Method ◽

Global Positioning ◽

Vector Tracking ◽

Tracking Loops ◽

And Performance

A number of methods have been developed to enhance the robustness of Global Positioning System (GPS) receivers when there are a limited number of visible satellites. Vector tracking is one of them. It utilizes information from all channels to aid the processing of individual channels to generate receiver positions and velocities. This paper analyzes relationships among code phase, carrier frequency, and receiver position and velocity, and presents a vector loop-tracking algorithm using an Extended Kalman filter implemented in a Matlab-based GPS software receiver. Simulated GPS signals are generated to test the proposed vector tracking method. The results show that when some of the satellites are blocked, the vector tracking loop provides better carrier frequency tracking results for the blocked signals and produces more accurate navigation solutions compared with traditional scalar tracking loops.

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